In order to maximize efficiency of limited radio resources, an effective transmission and reception scheme and various methods of utilization thereof have been proposed in a wireless communication system. A multiple-carrier system is one of systems considered in a next-generation wireless communication system. The multiple-carrier system implies a system which supports a broadband by aggregating one or more carriers having a bandwidth narrower than that of a desired broadband when a wireless communication system intends to support the broadband.
A wireless communication system such as conventional 3rd generation partnership project (3GPP) long term evolution (LTE) uses a carrier of various bandwidths, but is a single-carrier system which uses one carrier. Meanwhile, a next-generation wireless communication system such as LTE-A may be a multiple-carrier system which uses a plurality of carriers by aggregating the carriers.
In the multiple-carrier system, a user equipment (UE) can receive a plurality of data units through a plurality of downlink carriers, and can feed back a plurality of pieces of reception confirmation information (i.e., acknowledgement/not-acknowledgement (ACK/NACK)) for the plurality of data units to a base station (BS). In the multiple-carrier system, an amount of ACK/NACK information that must be fed back by the UE may be greater than that of the single-carrier system.
However, the LTE-A specifies that a plurality of ACK/NACK signals are transmitted through a specific uplink carrier. Accordingly, there is a need for a method and apparatus for reliably and effectively transmitting the plurality of ACK/NACK signals.